let a = new Set([1, 2, 3]);
let b = new Set([4, 3, 2]);

let intersect = new Set([...a].filter(x => b.has(x)))

console.log(intersect)

var msg = {
    eventType: 'a',
    a: 'b',
    c: 'd'
}
const {eventType, ...l} = msg;
console.log(l)